Abstract-This paper compared the performance of SVG and Flash when applied in WebGIS from different aspects, including basic characteristics, data storage, page rendering speed, interactivity etc. Through experiments and analysis, the result shows that: SVG and Flash can be used for visualizing WebGIS vector graphics. They are similar but have different characteristics. SVG, which is based on XML, has advantages in data exchange, transmission, integration and interoperability, it can be modified conveniently with low production cost. Flash has the advantage in terms of network animation, moreover, has high data compression, fast transmission and rendering speed. Finally, recommendations were made about how to choose vector map format in WebGIS.